Consider patent No. 6,362,718 for a " Motionless Electromagnetic Generator," granted in March of this year. The invention provides " a magnetic generator [in] which a need for an external power source during operation is eliminated." That is to say, once you start it up with a battery, it will keep on running and outputting power long after the battery is disconnected. Limitless power for next to nothing!
NPR just had a segment trashing the Wright brothers for enforcing their airplane patents against a rival who did similar work about 5 years later, and quoting folks who said that patents have been bad for the airplane industry and bad for a lot of other industries as well. One source was the book: Unlocking the Sky: The Race to Invent the Airplane by Seth Shulman.